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target/riscv: Fix the PMP is locked check when using TOR 

The RISC-V spec says:
    if PMP entry i is locked and pmpicfg.A is set to TOR, writes to
    pmpaddri-1 are ignored.

The current QEMU code ignores accesses to pmpaddri-1 and pmpcfgi-1 which
is incorrect.

Update the pmp_is_locked() function to not check the supporting fields
and instead enforce the lock functionality in the pmpaddr write operation.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-id: 2831241458163f445a89bd59c59990247265b0c6.1618812899.git.alistair.francis@wdc.com
This commit is contained in:
Alistair Francis 2021-04-19 16:16:25 +10:00
parent 0924a423ba
commit 94c6ba83c1
1 changed files with 16 additions and 10 deletions
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26
target/riscv/pmp.c
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@ -59,16 +59,6 @@ static inline int pmp_is_locked(CPURISCVState *env, uint32_t pmp_index)
return 0;
}
/* In TOR mode, need to check the lock bit of the next pmp
* (if there is a next)
*/
const uint8_t a_field =
pmp_get_a_field(env->pmp_state.pmp[pmp_index + 1].cfg_reg);
if ((env->pmp_state.pmp[pmp_index + 1u].cfg_reg & PMP_LOCK) &&
(PMP_AMATCH_TOR == a_field)) {
return 1;
}
return 0;
}
@ -380,7 +370,23 @@ void pmpaddr_csr_write(CPURISCVState *env, uint32_t addr_index,
target_ulong val)
{
trace_pmpaddr_csr_write(env->mhartid, addr_index, val);
if (addr_index < MAX_RISCV_PMPS) {
/*
* In TOR mode, need to check the lock bit of the next pmp
* (if there is a next).
*/
if (addr_index + 1 < MAX_RISCV_PMPS) {
uint8_t pmp_cfg = env->pmp_state.pmp[addr_index + 1].cfg_reg;
if (pmp_cfg & PMP_LOCK &&
PMP_AMATCH_TOR == pmp_get_a_field(pmp_cfg)) {
qemu_log_mask(LOG_GUEST_ERROR,
"ignoring pmpaddr write - pmpcfg + 1 locked\n");
return;
}
}
if (!pmp_is_locked(env, addr_index)) {
env->pmp_state.pmp[addr_index].addr_reg = val;
pmp_update_rule(env, addr_index);